What does the green wrench light on the ford f250 mean?

The green wrench light on a Ford F-250 is jokingly referred to as the "dealership needs $1,000" light by many folks on online forums. With that said, it indicates a general technical fault with Your F-250's system -- sometimes serious, sometimes moderate, or sometimes mild. Without reading the diagnostic trouble codes (DTCs) that come with it with an OBD-II scan tool, there's no way to whittle down the possibilities for You. You might have anything from a turbo overboost error to a diesel particulate filter issue to a bad oil cooler. The price range for fixing the error ranges wildly, from under $100 to over a few thousand, so I can't unfortunately give You a better starting point than simply reading Your DTCs.